1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the invention relates to devices and methods for enhancing cardiovascular valve repair, especially the repair of heart valves such as the mitral and tricuspid valves.
In recent years, many advances have been made to reduce the invasiveness of cardiac surgery. In an attempt to avoid open, stopped-heart procedures, which may be accompanied by high patient morbidity and mortality,: many devices and methods have been developed for operating on a heart through smaller incisions, operating on a beating heart, and even performing cardiac procedures via transvascular access. Different types of cardiac procedures, such as cardiac ablation techniques for treating atrial fibrillation, stenting procedures for atherosclerosis, and valve repair procedures for treating conditions such as mitral valve regurgitation have experienced significant technological advances. In implementing many minimally invasive cardiac surgery techniques, especially beating-heart techniques, one of the most significant challenges is positioning a treatment device (or multiple devices) in a desired location in or around the heart for performing the procedure. Another challenge, once a device is positioned, is to effectively deploy a given treatment into or on the target cardiac tissue.
One type of cardiac surgery which may benefit from less invasive techniques is heart valve repair. Traditional treatment of heart valve stenosis or regurgitation, such as mitral or tricuspid regurgitation, typically involves an open-heart surgical procedure to replace or repair the valve. Valve repair procedures typically involve annuloplasty, a set of techniques designed to restore the valve annulus shape and strengthen the annulus. Conventional annuloplasty surgery generally requires a large incision into the thorax of the patient (a thoracotomy), and sometimes a median sternotomy (cutting through the middle of the sternum). These open heart, open chest procedures routinely involve placing the patient on a cardiopulmonary bypass machine for sustained periods so that the patient's heart and lungs can be artificially stopped during the procedure. Finally, valve repair and replacement procedures are typically technically challenging and require a relatively large incision through the wall of the heart to access the valve.
Due to the highly invasive nature of open heart valve repair or replacement, many patients, such as elderly patients, patients having recently undergone other surgical procedures, patients with comorbid medical conditions, children, late-stage heart failure patients, and the like, are often considered too high-risk to undergo heart valve surgery and are relegated to progressive deterioration and cardiac enlargement. Often, such patients have no feasible alternative treatments for their heart valve conditions.
To obviate this situation, a number of devices and methods for repairing cardiac valves in a less invasive manner have been described. Some devices provide for heart valve repair through minimally invasive incisions or intravascularly, while others improve upon open heart surgical procedures on beating hearts, stopped hearts or both. As mentioned above, difficulties in performing minimally invasive intracardiac surgery include positioning a minimally invasive treatment device in a desired location for performing a procedure and effectively deploying a given treatment into or on the target cardiac tissue. In heart valve repair procedures, for example, it is often essential for a physician to secure one or more treatment devices to valve annulus tissue. Annular tissue tends to be more fibrous than surrounding muscular or valve leaflet tissue, thus providing a more suitable location for securing such treatment devices, such as anchors, to treat a heart valve. Positioning an anchor deliver device in a desired location adjacent the annular tissue may often be challenging, especially in an intravascular procedure when visualization of the location is limited.
Devices and methods that address these difficulties are described in U.S. Patent Application Nos. 60/445,890, 60/459,735, 60/462,502, 60/524,622, Ser. Nos. 10/461,043, and 10/656797, which were previously incorporated by reference. For example, these references describe devices and methods for exposing, stabilizing and/or performing a procedure on a heart valve annulus, such as a mitral valve annulus. Many of the devices and methods previously described by the inventors have been found to be highly effective, but improvements are still being sought.
Therefore, it would be beneficial to have improved devices and methods for performing a procedure on a heart valve annulus. Ideally, such devices could be conveniently positioned in a location for treatment of a valve annulus. Also ideally, such devices and methods would provide for enhanced delivery of treatment devices to a valve annulus, for example to enhance the securing of anchors to annular tissue. At least some of these objectives will be met by the present invention.
2. Description of the Background Art
Published U.S. Application 2002/0156526 describes a catheter-based method for performing annuloplasty. Published U.S. Application 2002/0042621 describes a heart valve annuloplasty system with constrictable plication bands which are optionally attached to a linkage strip. Published U.S. Application 2002/0087169 describes a remote controlled catheter system which can be used to deliver anchors and a tether for performing an annuloplasty procedure. Other patent publications of interest include WO01/26586; US2001/0005787; US2001/0014800; US2002/0013621; US2002/0029080; US2002/0035361; US2002/0042621; US2002/0095167; and US2003/0074012. U.S. Patents No. of interest include U.S. Pat. Nos. 4,014,492; 4,042,979; 4,043,504; 4,055,861; 4,700,250; 5,366,479; 5,450,860; 5,571,215; 5,674,279; 5,709,695; 5,752,518; 5,848,969;5,860,992; 5,904,651; 5,961,539; 5,972,004; 6,165,183; 6,197,017; 6,250,308; 6,260,552; 6,283,993; 6,269,819; 6,312,447; 6,332,893; and 6,524,338. Publications of interest include De Simone et al. (1993) Am. J. Cardiol. 73:721-722, and Downing et al. (2001) Heart Surgery Forum, Abstract 7025. All of the above cited references are hereby incorporated by reference in the present application.